Fuel container for fuel cell

ABSTRACT

A fuel container ( 1 ) for supplying fuel (F) to a fuel cell is constituted by: a container main body ( 2 ) having a sealed structure; an inner container ( 3 ) for housing the fuel therein, formed by a flexible bag provided within the container main body; a valve mechanism ( 4 ) for enabling/disabling supply of fuel, provided in the container main body ( 2 ) and in communication with the interior of the inner container ( 3 ); and compressed gas (G) for ejecting the fuel, sealed between the container main body ( 2 ) and the inner container ( 3 ). All of the structural components that contact the fuel (F) are formed of non-metallic materials. The fuel container ( 1 ) may also include an injection valve ( 5 ). In this case, a fuel injecting container reinjects fuel (F) into the fuel container ( 1 ), such that the fuel container ( 1 ) can be used repeatedly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel container for housing anddirectly supplying fuel, such as methanol solution, to a fuel cell, suchas a polymer electrolyte fuel cell (PEFC) The present invention alsorelates to a fuel container for reinjecting fuel into a fuel container,which is mounted on a fuel cell.

2. Description of the Related Art

Conventional containers for housing solutions include aerosolcontainers, and cosmetic containers, for example. Generally, glass,metal, or plastic is used as the material of the main bodies of thecontainers. These containers are pressurized such that when nozzlesthereof are opened, the solutions stored therein are sprayed out foruse.

In the containers described above, springs are utilized as urgingmembers for urging the nozzles in the closing direction. From theviewpoints of cost and ease of use, metallic coil springs are generallyused. However, in order to improve recycling rates, cylindrical urgingmembers constituted by elastic resin materials have been proposed (referto Japanese Unexamined Patent Publication No. 11 (1999)-90282, forexample)

The use of fuel cells as miniature power sources for devices such asportable computers (laptop PC's, PDA's and the like) is beingcontemplated. Fuel containers are necessary to supply fuel to these fuelcells. In the case that the fuel cell is a polymer electrolyte fuel cell(hereinafter, referred to simply as PEFC), methanol and distilled water,ethanol and distilled water, pure methanol, or pure ethanol is used asthe fuel therefor. In addition, dimethyl ether is expected to be used asfuel for solid oxide fuel cells (hereinafter, referred to simply asSOFC) and PEFC's.

However, in fuel cells such as SOFC's and PEFC's, contamination bymetallic ions is to be avoided. It has been found, therefore, that thefuel container must be constructed such that metallic ions do notcontaminate fuel housed therein.

It is inappropriate to employ metallic materials for members thatcontact the fuel, because ions will be generated. Even if the metallicmembers are coated with resin, generation of ions cannot be avoided, dueto pinholes in the resin film. In the case that interior pressure isapplied to the fuel container such that the fuel is ejected andsupplied, it is not preferable for the fuel to be supplied contaminatedby the pressurizing agent (propellant).

The shape of the fuel container is set according to the shape of thefuel cell itself, or the shape of a fuel container housing portion of adevice, such as a laptop PC. Therefore, it is disadvantageous from theviewpoint of cost to dispose of fuel containers, which have beenprovided in shapes according to specific devices, once the fuel thereinis consumed. In addition, such fuel containers easily become difficultto obtain, which is inconvenient.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the aforementionedpoints. It is an object of the present invention to provide a fuelcontainer for fuel cells that prevents contamination of fuel by metallicions and propellant, and which is reusable. It is another object of thepresent invention to provide a fuel container that reinjects fuel intofuel containers, which are mounted on fuel cells.

A first fuel container for housing fuel to be supplied to a fuel cell ofthe present invention comprises:

-   -   a container main body having a sealed structure;    -   an inner container for housing the fuel therein, formed by a        flexible bag provided within the container main body;    -   a valve mechanism for enabling/disabling supply of fuel,        provided in the container main body and in communication with        the interior of the inner container;    -   an injection valve for injecting fuel, provided in the container        main body and in communication with the interior of the inner        container; and    -   compressed gas for ejecting the fuel, sealed between the        container main body and the inner container;    -   all of the structural components that contact the fuel being        formed of non-metallic materials; and    -   the fuel container being mountable on the fuel cell to directly        supply fuel thereto.

A second fuel container for housing fuel to be supplied to a fuel cellof the present invention comprises:

-   -   a container main body having a sealed structure;    -   an inner container for housing the fuel therein, formed by a        flexible bag provided within the container main body;    -   a valve mechanism for enabling/disabling supply of fuel and for        injecting fuel, provided in the container main body and in        communication with the interior of the inner container; and    -   compressed gas for ejecting the fuel, sealed between the        container main body and the inner container;    -   all of the structural components that contact the fuel being        formed of non-metallic materials; and    -   the fuel container being mountable on the fuel cell to directly        supply fuel thereto.

A third fuel container for housing fuel to be supplied to a fuel cell ofthe present invention comprises:

-   -   a container main body having a sealed structure;    -   an inner container for housing the fuel therein, formed by a        flexible bag provided within the container main body;    -   a valve mechanism for enabling/disabling supply of fuel,        provided in the container main body and in communication with        the interior of the inner container; and    -   compressed gas for ejecting the fuel, sealed between the        container main body and the inner container at a pressure higher        than a fuel pressure of a fuel container, which is mounted on        the fuel cell to directly supply fuel thereto;    -   all of the structural components that contact the fuel being        formed of non-metallic materials; and    -   the fuel container being mountable on the fuel container, which        is mounted on the fuel cell, to reinject fuel therein.

A fourth fuel container for housing fuel to be supplied to a fuel cellof the present invention comprises:

-   -   a cylindrical container main body for housing the fuel therein;    -   a piston shaped extruding member, which is manually operated to        slide within the container main body in an airtight manner so as        to pressurize the fuel;    -   a valve mechanism for enabling/disabling supply of fuel,        provided in the container main body;    -   all of the structural components that contact the fuel being        formed of non-metallic materials; and    -   the fuel container being mountable on a fuel container, which is        mounted on the fuel cell, to reinject fuel therein.

It is preferable for the container main body of each of the above fuelcontainers to be formed by a transparent material.

The fuel containers of the present invention are suited to house fuelsfor PEFC's, such as methanol and distilled water, ethanol and distilledwater, pure methanol, and pure ethanol. The fuel containers of thepresent invention may also be utilized to house fuel for SOFC's andPEFC's, such as dimethyl ether.

Each of the fuel containers of the present invention comprises: acontainer main body; an inner container for housing fuel; and a valvemechanism for enabling/disabling supply of fuel. All of the structuralcomponents that contact the fuel are formed by non-metallic materials,and compressed gas is sealed between the container main body and theinner container. Therefor, only the fuel can be ejected and supplied.Further, contamination by metallic ions can be prevented, because thehoused fuel does not contact any metal. Particularly, in fuel cells suchas PEFC's, contamination of fuel, such as methanol solution and ethanolsolution by metallic ions is to be avoided. By forming the members thatcontact the fuel with non-metallic materials, the release of metallicions can be avoided. Thereby, fuel containers to be mounted onto fuelcells to directly supply fuel thereto, and fuel containers to reinjectfuel to fuel containers, which are mounted onto fuel cells, can beproduced without decreasing the performance of the fuel cells.

That is, in the case that the fuel container comprises an injectionvalve, through which fuel can be reinjected, or if the valve mechanismis configured to enable both supply and injection, users can easilyrefill the fuel container, by utilizing a fuel container configured toreinject fuel. This is advantageous from the viewpoint of cost, and thedegree of freedom regarding shapes corresponding to devices is improved.In addition, additional fuel will become commonly available, byproviding universal reinjecting fuel containers, which will improveconvenience.

Particularly in fuel containers that comprise injection valves separatefrom the valve mechanism to be connected to fuel cells, it is possibleto reinject fuel through the injection valves while the fuel containersare mounted on the fuel cells. On the other hand, in fuel containersthat comprise valve mechanisms that enable both supply and injection offuel, it is necessary to disconnect the fuel containers from fuel cellsto reinject fuel therein. However, separate injection valves can beomitted, simplifying the structure of the fuel containers.

In the third fuel container of the present invention, compressed gas forejecting the fuel is sealed between the container main body and theinner container at a pressure higher than a fuel pressure of a fuelcontainer, which is mounted on the fuel cell to directly supply fuelthereto. The fourth fuel container of the present invention comprises: acylindrical container main body for housing the fuel therein; and apiston shaped extruding member, which is manually operated. The thirdand fourth fuel containers are capable of reinjecting fuel into fuelcontainers that directly supply fuel to fuel cells. The shapes of thethird and fourth fuel containers can be set as desired. The third andfourth fuel containers can be constructed according to considerationsregarding fuel capacity and portability, thereby improving convenience.

The container main body of each of the fuel containers of the presentinvention may be formed by a transparent material. In this case, theamount of remaining fuel and states of reinjection can be visuallyconfirmed.

In addition, forming the fuel containers from resin exhibits thefollowing advantageous effects. The fuel containers may be formed intovarious shapes, such as cylinders, polygons, ovals, and the like.Classification during disposal is facilitated, which is suitable forrecycling. Thermal properties are favorable compared to metal, which iscold to the touch. Changes in the contents due to corrosion are notlikely to occur.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view illustrating a fuel container to bemounted on a fuel cell, according to a first embodiment of the presentinvention.

FIG. 2A is a sectional view of the main parts of a valve mechanism.

FIG. 2B is a sectional view of the main parts of an alternate valvemechanism.

FIG. 3 is a schematic sectional view illustrating a fuel container to bemounted on a fuel cell, according to a second embodiment of the presentinvention.

FIG. 4 is a schematic sectional view illustrating a fuel container forreinjecting fuel, according to a third embodiment of the presentinvention.

FIG. 5 is a schematic sectional view illustrating a fuel container forreinjecting fuel, according to a fourth embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the attached drawings. FIG. 1 is a schematicsectional view illustrating a fuel container 1 to be mounted on a fuelcell, according to a first embodiment of the present invention. FIGS. 2Aand 2B are sectional view of main parts of valve mechanisms.

The fuel container 1 of the first embodiment houses a methanol/distilledwater solution at a predetermined concentration, a ethanol/distilledwater solution at a predetermined concentration, pure methanol, or pureethanol as fuel F. The fuel container 1 supplies the fuel F to PEFC'sand the like. The fuel container 1 is mounted onto a fuel cell main body(not shown). It is possible to reinject fuel into the fuel container 1by using reinjecting fuel containers 10, 20 to be described later, andto use the fuel container 1 repeatedly.

As illustrated in FIG. 1, the fuel container 1 comprises: an outercontainer main body 2; an inner container 3 for housing the fuel Ftherein, formed by a flexible bag provided within the container mainbody 2; a valve mechanism 4 for opening and closing an upper supplyopening 2 a that communicates the interior of the inner container 3 withthe exterior of the container main body 2 to supply fuel; an injectionvalve 5 for opening and closing a lower injection opening 2 b, providedopposite the supply opening 2 a, that communicates the interior of theinner container 3 with the exterior of the container main body 2,through which fuel is injected; and a dip tube 6, which is inserted intothe interior of the inner container 3 from the valve mechanism 4. All ofthe parts, and particularly the parts that contact the fuel F, areformed by non-metallic materials, that is, resin. The space between thecontainer main body 2 and the inner container 3 is airtight, andcompressed gas G for applying ejection pressure for the fuel F to theinner container 3 is sealed in this space.

The container main body 2 is formed as a sealed box. The shape of thecontainer main body 2 is set according to the shape of the fuel cellmain body (not shown), or to the shape of a fuel container housingportion of a device, such as a laptop PC, in which the fuel cell ismounted. The shape can be varied as desired, in order to secure apredetermined inner capacity. The structure and wall thickness of thecontainer main body 2 are designed to have compressive strength capableof withstanding the pressure of the contents. The outer container mainbody 2 is formed by a transparent material, such as transparent PC, PAN,PEN, PET, and the like, such that the amount of fuel F remaining withinthe inner container 3 can be visually confirmed.

Meanwhile, the inner container 3 has resistance with respect to the fuelF. A bag, formed by sheets of rubber film, PAN, PEN or the like, whichare coated with ceramic by vapor deposition and sealed together, orformed by sheets of PE, PP or the like, which are coated with metal foil(aluminum foil, for example) and sealed together, is fixed to the supplyopening 2 a and the injection opening 2 b of the container main body 2in a sealed state. The inner container 3 is impermeable with respect togases. The volume of the inner container 3 is set such that a fuelhousing ratio with respect to the entire volume of the container mainbody 2 is maximized.

Air, nitrogen, or carbon dioxide is employed as the compressed gas G,which is sealed between the container main body 2 and the innercontainer 3. In the case that a gas that does not contain oxygen, suchas nitrogen, is employed, oxidation of the fuel F (particularlymethanol) by trace amounts of oxygen that permeates through the innercontainer 3 can be prevented. By employing compressed gas, variations inpressure due to temperature change of the container main body arereduced, compared to cases in which liquefied gas is employed.

The valve mechanism 4 is provided within the supply opening 2 a, whichis formed as a protrusive cylinder at a portion (the upper portion inFIG. 1) of the container main body 2. Specific examples of the valvemechanism will be described with reference to FIG. 2A and FIG. 2B. Thevalve mechanism 4 comprises a flow rate adjusting mechanism 7 and aresistance mechanism 8. In the example illustrated in FIG. 2A, the flowrate adjusting mechanism 7 (the detailed structure of which is notshown) is provided at the open portion of the supply opening 2 a of thecontainer main body 2 (the portion that connects with the fuel cell),and the valve mechanism 4 is provided beneath the flow rate adjustingmechanism 7. On the other hand, in the example illustrated in FIG. 2B,the valve mechanism 4 is provided at the open portion of the supplyopening 2 a of the container main body 2 (the portion that connects withthe fuel cell), and the rate adjusting mechanism 7 is provided beneaththe valve mechanism 4. The basic structure of the valve mechanism 4 isthe same between the examples of FIG. 2A and FIG. 2B, and will bedescribed employing the same reference numerals.

The valve mechanism 4 comprises: a guiding screw 41 for fixing the valvemechanism to the container main body 2; a gasket 42 forenabling/disabling supply of the fuel F by functioning as a valve; avalve stem 43, which is the operating member that opens and closes thevalve; a resin spring 44 that functions as an urging member for urgingthe valve stem 43 in the closing direction; and a valve housing 45 forhousing the resin spring 44. All of the above components are formed bynon-metallic materials.

The valve housing 45 is mounted onto the supply opening 2 a of thecontainer main body 2. In the example of FIG. 2B, the flow rateadjusting mechanism 7 is built in to the bottom of the valve housing 45in advance. Assembly of the valve mechanism 4 will be described. Theresin spring 44 is inserted into the valve housing 45, the valve stem 43is inserted atop the resin spring 44, the gasket 42 is fitted about theouter periphery of the valve stem 43, and the guide screw 41 isthreadedly engaged with the container main body 2 to build the valvemechanism 4 into the container main body 2. The valve stem 43 is urgedby the resin spring 44 toward the guide screw 41, and the outerperiphery of the gasket 42 is held and fixed to the container main body2 by the guide screw 41.

A peripheral groove is formed in the outer periphery of the valve stem43. Fine openings, which are open at the bottom of the peripheralgroove, communicate with a central path, and the central path opens intoan upper ejection opening. The gasket 42 is fitted into the peripheralgroove of the valve stem 43. Elastic close contact of the innerperipheral surface of the gasket 42 seals the fine openings, to shut offsupply of the fuel F. When the fuel container 1 is connected to the fuelcell, the valve stem 43 is pressed inward against the resin spring 44,via the flow rate adjusting mechanism 7 in the example of FIG. 2A, anddirectly in the example of FIG. 2B. Accompanying the downward movementof the valve stem 43, the inner peripheral portion of the gasket 42deforms to open the fine openings. Thereby, the fuel F is supplied intothe valve housing 45 by the dip tube 6, via the flow rate adjustingmechanism 7, in the example of FIG. 2B. Then, the fuel F, which hasflowed into the valve housing 45, is supplied to the fuel cell via thecentral path of the valve stem 43, via the flow rate adjusting mechanism7 in the example of FIG. 2A, and directly in the example of FIG. 2B.

The resin spring 44 that functions as the urging member comprises: adiscoid base for holding the position of the lower end; an abuttingportion for abutting the bottom of the valve stem 43 to transfer urgingforce thereto; and a folded deforming portion that links the base andthe abutting portion. The resin spring 44 is molded from polyacetal(POM), for example.

A compressive structure of a filter constitutes the flow rate adjustingmechanism 7, for example. A filter formed by urethane foam may beprovided in a fuel flow path in a compressed state. The flow rate of thefuel F may be adjusted by varying the compression of the filter.Thereby, abrupt ejection of the fuel F is suppressed, and the load on aflow rate adjusting mechanism of the fuel cell is reduced. In addition,the resistance mechanism 8 is provided in the valve mechanism 4, toprevent inadvertent opening operations thereof. In the examplesillustrated in FIG. 2A and FIG. 2B, the periphery of the edge of thesupply opening 2 a is formed toward the exterior of the tip of the valvestem 43, to constitute the resistance mechanism 8. The resistancemechanism 8 prevents other members from contacting the tip of the valvestem 43.

The injection valve 5 is of the same basic structure as the valvemechanism 4. However, the flow rate adjusting mechanism 7 may be omittedfrom the injection valve 5.

The fuel container 1 described above ejects the fuel F with a pressurewithin a predetermined range. The fuel container 1 is of a doublestructure comprising the container main body 2 and the inner container3, so as to prevent contents other than the fuel F from being ejected.Therefore, fuel leaks due to shocks, imparted by the fuel container 1being dropped or the like, can be prevented. In addition, the fuelcontainer 1 can adapt to the requirements for high space efficiencydemanded in laptop PC's and PDA's. A compact fuel container having alarge capacity can be realized. In addition, the fuel container 1comprises the injection valve 5 separate from the valve mechanism 4.Therefore, fuel can be reinjected into the fuel container 1, withoutremoving it from the fuel cell.

The fuel container 1 of the first embodiment suited to house fuels suchas methanol and distilled water, ethanol and distilled water, puremethanol, and pure ethanol. The fuel container 1 of the first embodimentmay also be utilized to house fuel for SOFC's and PEFC's, such asdimethyl ether. Dimethyl ether is gaseous at room temperature, but maybe compressed into liquefied gas and injected into the fuel container 1.In this case, the liquefied dimethyl ether itself possesses ejectionpressure. Therefore, compressed gas need not be sealed between thecontainer main body 2 and the inner container 3. Liquefied dimethylether exerts high pressure, which necessitates a pressure resistantconstruction. In addition, a construction which is resistant tosolubility due to the dimethyl ether is also necessary. The fuelcontainer 1 is of a double structure. Accordingly, the inner container 3maybe of a construction that is resistant against solubility by dimethylether, and also leak proof, while the container main body 2 may be of aconstruction which is resistant to cracking and deformation due topressure.

FIG. 3 is a schematic sectional view illustrating a fuel container 1′according to a second embodiment of the present invention. The functionof the injection valve 5 of the first embodiment is imparted to thevalve mechanism 4 at the supply opening 2 a in the fuel container 1′,and a separate injection valve is omitted. The other structures of thefuel container 1′ are the same as those of the fuel container 1 of thefirst embodiment. The following description will employ the samereference numerals as those of the first embodiment for commonstructures, and detailed descriptions thereof will be omitted.

In the second embodiment, supply of the fuel F to the fuel cell andreinjection of fuel into the fuel container 1′ are performed throughopening and closing operations of the valve mechanism 4 illustrated inFIG. 2A and 2B. When reinjecting fuel, it is necessary to remove thefuel container 1′ from the fuel cell. However, the structure of the fuelcontainer 1′ is simplified.

In the fuel containers 1 and 1′ of the first and second embodiments, tobe mounted onto the fuel cell, the parts that contact the fuel F areformed by resin. Thereby, metallic ions do not contaminate the fuel Ffor fuel cells, such as methanol solution and ethanol solution. Inaddition, there is no contamination of the fuel F by propellant.Accordingly, a favorable fuel container for PEFC's, for which thepresence of metallic ions is to be avoided, can be realized. The fuelcontainers 1 and 1′ do not decrease the performance of the fuel cell,and can be utilized repeatedly, by reinjecting fuel therein.

FIG. 4 and FIG. 5 are schematic sectional views of injecting fuelcontainers 10 and 20 according to a third and fourth embodiments of thepresent invention, respectively. The injecting fuel containers 10 and 20are utilized to reinject fuel into the inner containers 3 of the fuelcontainers 1 and 1′, when the amount of fuel therein decreases.

The injecting fuel container 10 illustrated in FIG. 4 comprises: acontainer main body 12; an inner container 13 formed by a flexible bag;a valve mechanism 14 (nozzle mechanism); a resistance mechanism 15; anda dip tube 16. The basic construction of the injecting fuel container 10is the same as that of the fuel containers 1 and 1′. Fuel F is housed inthe interior of the inner container 13, and compressed gas G forapplying ejection pressure is sealed between the container main body 12and the inner container 13. The valve mechanism 14 is configured to beconnected to the injection valve 5 of the fuel container 1 or to thevalve mechanism 4 of the fuel container 1′, to inject the fuel F intothe fuel container 1 or 1′ by the pressure applied by the compressed gasG.

The pressure of the compressed gas G, which is sealed within theinjecting fuel container 10, is set to be higher than the pressure ofthe compressed gas G, which is sealed within the fuel containers 1 and1′. Thereby, the fuel F can be sufficiently injected into the fuelcontainer 1 or 1′, even if the amount of fuel F remaining in theinjecting fuel container 10 becomes low.

The valve mechanism 14 is basically of the same construction as thevalve mechanisms 4 illustrated in FIG. 2A and FIG. 2B. However, the tipof a valve stem of the valve mechanism 14 protrudes outward, and isconfigured to press the valve stem 43 of the valve mechanism 4, therebyopening the fuel flow path thereof to inject the fuel F.

The resistance mechanism 15 prevents ejection of the fuel F due toinadvertent opening of the valve mechanism 14. The resistance mechanism15 is constituted by a cylindrical wall formed about the periphery ofthe valve mechanism 14, for example. The resistance mechanism 15 isdesigned so as not to be impeded by the injection valve 5 or the valvemechanism 4 when reinjecting fuel into the fuel container 1 or the fuelcontainer 1′.

The injecting fuel container 20 illustrated in FIG. 5 according to thefourth embodiment of the present invention is manually operated, and nocompressed gas is sealed therein. The injecting fuel container 20comprises: a cylindrical container main body 21; a piston shapedextruding member 22, which is manually operated to slide within thecontainer main body in an airtight manner; a valve mechanism 23 (nozzlemechanism), provided at the tip of the container main body 21; a lidmember 24, for sealing the end of the container main body 21 oppositethat of the valve mechanism 23; and a resistance mechanism 25. Fuel F issuctioned into the container main body 21 by retracting the extrudingmember 22. The fuel F is pressurized by advancing an operating section22 a of the extruding member 22, and injected into the inner container 3of the fuel container 1 or 1′, via the valve mechanism 23.

Engaging protrusions 21 a are provided at portions of the container mainbody 21 that link with the lid member 24. The engaging protrusions 21 afunction to prevent the lid member 22 from being disengaged from thecontainer main body 21, in case that fuel remaining in the fuelcontainer 1 or 1′ flow into the container main body 21 when theinjecting fuel container 20 is connected thereto.

The parts that contact the fuel F of the injecting fuel containers 10and 20 are also formed by non-metallic materials, that is, resin.Thereby, contamination of the fuel F by metallic ions is prevented. Inaddition, the container main bodies 12 and 21 are formed by transparentmaterials, to enable visual confirmation of the contents thereof.Further, the shapes of the container main bodies 12 and 21 can bedesigned as desired, taking fuel capacity, portability, and the likeinto consideration.

PE, PP, AS, ABS, PAN, PA, PET, PBT, PC, POM, PEN, and the like may bethe resin to be employed as the material of the parts that contact thefuel F in the fuel containers 1, 1′ and the injecting fuel containers10, 20. The material is selected on the basis of the intended contents,strength of the material, and the like. For example, if resistanceagainst methanol is taken into consideration, polyethylene (PE),polypropylene (PP), polyethylene naphthalate (PEN), and poly acrylonitrile (PAN) are superior and preferred. Acrylonitrile butadienestyrene (ABS), polyamide (PA), or polyacetal (POM) may also be employed.If resistance against ethanol is taken into consideration, polyethylene(PE), polypropylene (PP), polyamide (PA), polyacetal (POM), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), and poly acrylonitrile (PAN) are superior and preferred. Acrylonitrile butadienestyrene (ABS) may also be employed.

If resistance against dimethyl ether is taken into consideration,crystalline resins, such as polyamide (PA), polyacetal (POM), polybutilene terephthalate (PBT), and polypropylene (PP) may be employed.Alternatively, non-crystalline resins, such as acetal, polycarbonate,and acrylo nitrile butadiene styrene, may be employed to form the parts,and the surfaces thereof may be coated with epoxy resin or polyamideresin.

A single layer structure, formed by a single material, or a double(multiple) layer structure, formed by a plurality of materials, maybeemployed. In the case that the double layer structure is employed, amaterial having superior resistance is employed for the inner layer thatcontacts the contents, and a pressure and shock resistant material isemployed as the outer layer. Fuel containers employing the double layerstructure may be formed by a double injection molding method, or by acoating method.

1. A fuel container for housing fuel to be supplied to a fuel cell,comprising: a container main body having a sealed structure; an innercontainer for housing the fuel therein, formed by a flexible bagprovided within the container main body; a valve mechanism forenabling/disabling supply of fuel, provided in the container main bodyand in communication with the interior of the inner container; aninjection valve for injecting fuel, provided in the container main bodyand in communication with the interior of the inner container; andcompressed gas for ejecting the fuel, sealed between the container mainbody and the inner container; all of the structural components thatcontact the fuel being formed of non-metallic materials; and the fuelcontainer being mountable on the fuel cell to directly supply fuelthereto.
 2. A fuel container for housing fuel to be supplied to a fuelcell, comprising: a container main body having a sealed structure; aninner container for housing the fuel therein, formed by a flexible bagprovided within the container main body; a valve mechanism forenabling/disabling supply of fuel and for injecting fuel, provided inthe container main body and in communication with the interior of theinner container; and compressed gas for ejecting the fuel, sealedbetween the container main body and the inner container; all of thestructural components that contact the fuel being formed of non-metallicmaterials; and the fuel container being mountable on the fuel cell todirectly supply fuel thereto.
 3. A fuel container for housing fuel to besupplied to a fuel cell, comprising: a container main body having asealed structure; an inner container for housing the fuel therein,formed by a flexible bag provided within the container main body; avalve mechanism for enabling/disabling supply of fuel, provided in thecontainer main body and in communication with the interior of the innercontainer; and compressed gas for ejecting the fuel, sealed between thecontainer main body and the inner container at a pressure higher than afuel pressure of a fuel container, which is mounted on the fuel cell todirectly supply fuel thereto; all of the structural components-thatcontact the fuel being formed of non-metallic materials; and the fuelcontainer being mountable on the fuel container, which is mounted on thefuel cell, to reinject fuel therein.
 4. A fuel container for housingfuel to be supplied to a fuel cell, comprising: a cylindrical containermain body for housing the fuel therein; a piston shaped extrudingmember, which is manually operated to slide within the container mainbody in an airtight manner so as to pressurize the fuel; a valvemechanism for enabling/disabling supply of fuel, provided in thecontainer main body; all of the structural components that contact thefuel being formed of non-metallic materials; and the fuel containerbeing mountable on a fuel container, which is mounted on the fuel cell,to reinject fuel therein.
 5. A fuel container as defined in any one ofclaims 1 through 4, wherein: the container main body is formed by atransparent material.